first.octopus

I got my 08 A6 CPO from an Audi dealer. Just completed the 55K service myself. I noticed that the rear belly pan was missing. Got a replacement rear belly pan from ebay. It fit perfectly. However, I can't find the correct fastener to install the pan.

I went to an Audi dealer. They gave me these nut and pin. The nut did not fit into the square hole. Bring them back to dealer. The part guy could not figure out...

Just wondering who know what are the fastener to install the rear belly pan. or Did my car missing an intermediate part before putting in the nut?

Here are some pic that may help to explain...

Please note that rear belly pan is marked as #2 in the diagram.

A6Gary

The first image is the speed nut that the dowel pin (third image, #2 in the forth image) engages using a CW half turn to secure the rear belly pan. The speed nut should lip over the lip in that rectangular hole in the part in the second image. You're not missing any body parts.

MainlandMig

no time to try to sneak a peek underneath but my guess is it fits this way
but to be sure place the nut on the belly pan and test fit it to see where it would connect/rest